Tunable, high-power, solid-state sources for the blue and ultraviolet

We describe new sources of tunable, high-power radiation in the blue and ultraviolet. Continuous-wave (cw), singlefrequency blue radiation tunable across 425-489 nm and femtosecond ultraviolet (UV) radiation tunable across 250-355 nm is generated by intracavity frequency-doubling of resonant signal radiation in cw and ultrafast optical parametric oscillators (OPOs) in singly-resonant oscillator (SRO) configuration. The cw SRO, pumped in the green, uses a 30-mm MgO:sPPLT as the nonlinear material and a 5-mm BiB3O6 (BIBO) crystal for internal doubling. Using this approach, we generate 1.27 W of cw blue power with a linewidth of 8.5 MHz and a TEM00 profile. The device also generate a singlefrequency signal output of ~100 mW across 850-978 nm and up to 2.6 W of idler power in the 1167-1422 nm spectral range. The femtosecond SRO, based on a 400-μm BIBO crystal and pumped at 415 nm in the blue, can provide visible femtosecond signal pulses across 500-710 nm. Using a 500-μm crystal of β-BaB2O4 internal to the SRO cavity, efficient frequency doubling of the signal pulses into the UV is achieved, providing tunable femtosecond pulses across 250-355 nm with up to 225 mW of average power at 76 MHz. Cross-correlation measurements result in UV pulses with durations down to 132 fs for 180 fs blue pump pulses.